1. Department of Neurology, Keio University School of Medicine, Tokyo, Japan
2. Japanese Red Cross Ashikaga Hospital, Ashikaga, Japan
3. Department of Infectious Diseases, Keio University School of Medicine, Tokyo, Japan
4. Division of Drug Informatics, Keio University Faculty of Pharmacy, Tokyo, Japan
5. Department of Neurology, Japanese Red Cross Shizuoka Hospital, Shizuoka, Japan
6. Headache Unit, Department of Neurology, Hospital Clínico Universitario de Valladolid, Valladolid, Spain
7. School of Health Sciences, Unitelma Sapienza University of Rome, Rome, Italy